When Chinese dissident Sheng Xue fled to Canada, she thought she had finally escaped the watchful eye of Chinese authorities.

But late one winter’s night, a car pulled up outside her Toronto home.

It marked the beginning of many such clandestine visits by people she believes to be Chinese agents.

Xue, who was granted asylum in Canada, says they contacted her repeatedly, warning they were tracking her every move and threatening to kill her if she continued to criticise China’s leaders.

“I thought that I escaped from the fear,” says Xue. “I was going to enjoy freedom, human rights, democracy and the rule of law. But I realised that they are here, their people, their network, their power, and everything is here.”

Following death threats by people claiming to be Chinese agents, Sheng Xue says she’s often had vehicles with suspicious-looking men inside park in front of her Toronto home at night. [Al Jazeera]

Chinese authorities have long been accused of silencing their critics at home but now it seems their threatening methods of censorship and surveillance are extending to activists who have fled to the supposed safety of foreign soil.

In this exclusive investigation, 101 East reveals that China is taking extreme measures to silence anyone who speaks out against its government.

Interviews with more than 20 activists and journalists in countries like the US, Canada and Australia, paint a disturbing picture of how China uses intimidation and harassment to control overseas dissent.

I was kidnapped by the Chinese secret police. I didn’t know where I was detained. And then I was physically tortured.

Teng Biao, former China-based civil rights lawyer

Some say they have received death threats and been confronted by Chinese agents in their new countries. Others say they have been victims of blackmail and intimidation.

“Chinese authorities took photos of my son while he was on his way to school,” says Wen Yunchao, a well-known Chinese blogger who moved his family to New York. “They just wanted to let me know that at any time they can harm my child … forcing me to do what they want.”

‘Kidnapped by the Chinese secret police’

Activists say criticising Chinese leaders or supporting groups perceived as threats to the nation, such as Falun Gong, Tibetans or Uyghurs, can be enough to attract the authorities’ attention.

Teng Biao says he experienced the dangers of speaking out while working as a civil rights lawyer in China. He fled to the US in 2014 after being targeted by Chinese authorities.

“I was kidnapped by the Chinese secret police. I didn’t know where I was detained. And then, I was physically tortured,” he says.

He shows Al Jazeera death threats he says he’s received online since moving to the US. He believes they were sent by Chinese agents.

One reads: “Teng Biao take care of your life because you will be murdered.”

After he left China, Teng said his family was barred from leaving the country so he hatched a risky escape plan to smuggle them out to safety.

China expert Jerome Cohen

But many dissidents living abroad continue to fear for family members back home.

In a rare interview with a Chinese government insider, a former high-level diplomat reveals the country’s strategy of silencing dissent abroad.

“If they get involved in any anti-communist group, they would definitely be harmed. It happens,” says Chen Yonglin, who defected to Australia in 2005. “Most of the Chinese immigrants are still scared because they know the Chinese regime may go to extreme means.”

“Xi Jinping thinks there must be unquestionable acceptance of the party line, the party must control everything and that’s the only way China will meet the formidable problems it faces today.”

Blind human rights lawyer Chen Guangcheng fled China for the US in May 2012. Since then, Chen and his wife say they’ve received repeated threats from Chinese authorities. [Al Jazeera]

China’s global web of spies and informants

While Chinese dissidents fear for their own safety, concerns are also growing over China’s increasing influence over key institutions in countries like the US, Canada and Australia.

In the US, the FBI and CIA recently accused China of using a global web of spies and informants to intimidate and neutralise its critics.

“The biggest issue of our time, in my view, is China and the risk they pose,” Senator Marco Rubio told a congressional hearing in Washington in February. “I’m not sure in the 240-some-odd-year history of this nation we’ve ever faced a competitor and potential adversary to have this scale, scope and capacity.”

One of the greatest concerns relates to the 500 Confucius Institutes China operates at universities around the world.

The centres claim to teach Chinese culture and language, but critics say they are a propaganda tool.

“On campus … they can build up a friendly network to China and can influence the future generations of the Western countries,” says Chen Yonglin, the defector. “Politically sensitive topics are banned. Topics like Falun Gong, democracy and freedom, human rights in China – all banned.”

But the director of the Confucius Institute at the University of Massachusetts in Boston denies that it serves as an arm of the Chinese government.

“Every Confucius Institute is working to be a bridge between the US and China,” says Beifang Sun. “We have nothing to do with the Chinese government’s censorship.”

I’m not sure in the 240-some-odd-year history of this nation we’ve ever faced a competitor and potential adversary to [have] this scale, scope and capacity.

Junior US senator to Florida, Marco Rubio

‘Democracy and human dignity will prevail’

When it comes to the alleged threats to Chinese activists overseas, the Chinese government denied the allegations.

“Regarding those groundless accusations, we really do not want to waste time responding to them one by one,” Hua Chunying, a foreign ministry spokesperson said last month.

“We hope that relevant people can abandon the Cold War mentality and zero-sum game mindset and create favourable conditions for the sound development of our relations with an open and inclusive attitude.”

But activists like Teng Biao say it’s time for democratic countries to take a stand and do more to support those living under China’s shadow.

“There are always activists and heroes willing to sacrifice themselves to speak out, to fight against these atrocities and the dictatorship,” he says.